Pharmacokinetic evaluation of stable piecewise cubic polynomials as numerical integration functions.

A numerical integration method based on piecewise cubic polynomial for computing the area under the curve in pharmacokinetics is presented. The method has been found to produce stable and monotone interpolations irrespective of experimental error. Spurious oscillations occasionally associated with cubic splines are eliminated. Comparisons with the previously available methods suggest that more reliable and less biased areas under the plasma concentration curve, AUC, or areas under the first moment of plasma curve, AUMC, can be generated by the present method.